package Lesson;

public class Lesson {
    public static void main(String[] args) {
        String version = System.getProperty("java.version");
        System.out.println(version);
        String use = System.getProperty("user.dir");
        System.out.println(use);



        Integer x = Integer.valueOf("4");
        int a = x.intValue();
        System.out.println(a);


        Integer b = 5;  //等价Integer b = new Integer(5)

        Integer b1 = Integer.valueOf(6);
        int b2 = b1+2;   //等价int a1 = b1.intValue()+2
    }
}
